Review on application of molybdenum disilicide
Wang Xia Jiang Wen
School of Materials Science and Engineering, Southwest Petroleum University, Chengdu 610500, Sichuan
Abstract: In this paper, the properties of molybdenum disilicide are briefly described, the applications of molybdenum disilicide materials in high-temperature structural materials, heating elements, coatings and other aspects are reviewed, and the development and application prospects of molybdenum disilicide and its composites in the future are forecasted.
Keywords: molybdenum disilicide high temperature structural material composite material heating element coating
Molybdenum disilicide (MoSi2) has the dual characteristics of metal and ceramic. It has a high melting point (2303K), relatively low density, good high-temperature oxidation resistance, thermal shock resistance, and stable resistance, conductivity, thermal conductivity. It also has a high brittle ductile transition temperature. It is a high-temperature heating material and structural high-temperature material widely used in aerospace and other fields . Therefore, molybdenum disilicide, like other ceramic materials, can be used as another high temperature resistant material product, which is widely valued by various material scientists and becomes one of the research focuses of various material scholars.
1 High temperature structural materials
In recent years, with the continuous progress of aerospace technology, more stringent requirements have been put forward for the performance of high-temperature structural materials. MoSi2 has a variety of excellent properties, thus hiding huge application potential. It is considered to be one of the most promising high-temperature materials, and has become one of the research hotspots in the field of materials science . Because MoSi2 material has a very high melting point, good oxidation resistance and proper specific gravity are the main performance parameters to determine whether to choose it as a high-temperature structural material in the aerospace field. MoSi2 is very stable in the oxidation atmosphere below 1750 ℃, and its yield strength will not decrease even when the temperature rises to 1400 ℃.
2 Molybdenum disilicide matrix composite
As mentioned above, intermetallic compound molybdenum disilicide has a series of good properties, including high melting point, excellent oxidation resistance, and good electrical and thermal conductivity, so it can be widely used as a composite material. The oxidation resistance and high temperature resistance of MoSi2 can be used to prepare coatings and films on the surface of metals or easily oxidized materials, which can enhance the oxidation resistance of materials . Therefore, the preparation of MoSi2 based composites, namely MoSi2 composite, is another effective way to improve the mechanical properties of MoSi2.
3 Heating element
Up to now, MoSi 2 material has the most extensive commercial application as a heating element in high temperature oxidation gas at 1600 ℃ and above. Because molybdenum disilicide has excellent oxidation resistance and mechanical properties, MoSi2 has been widely used as a heating element. However, sometimes due to the insufficient fineness and purity of raw materials, the final performance is poor, and there are certain defects in its oxidation resistance and mechanical properties. For heating elements with special shapes, there is no other processing and creative ability, leading to insufficient service life. The molding and manufacturing process of all heating elements need to be improved to be more widely used in the market .
MoSi2 materials were first used as high-temperature oxidation resistant coatings in the field of anti-corrosion, which is also a relatively mature application. According to its high-temperature oxidation resistance, it is mainly used as a coating material in refractory metals, superalloys, graphite, C/C composites and other coating materials . When preparing MoSi2 coating, a comparison will be generated on MoSi2 surface in high-temperature oxidation environment
Thin, protective SiO2 film. This protective film has good oxidation resistance at high temperature, so it has good corrosion resistance. Moreover, the MoSi2 coating produced has high hardness and can be used to prevent abrasion, scratch and diffusion barrier, so it can become a hard coating.
5 Other applications
In addition to being widely used in the above fields, MoSi2 materials can also be used as high-temperature heat exchangers, gas burners, high-temperature thermocouples, circuit grids and ceramic connection materials. Some people use MoSi2 material instead of aluminum wire as a connector of integrated circuit semiconductor, and even some people deposit MoSi2 material on quartz to prepare high-performance VLSI mask materials . It can be seen that MoSi2 and its composites have their applications in many fields.
Molybdenum disilicide is a kind of very promising product. Although it has been studied for many years as a high-temperature structural material, in addition to being used as a heating element and coating material, the research on high-temperature structural materials is still in the stage of theoretical exploration, and has not been widely used in semiconductor, microelectronics, corrosion and other fields. MoSi2 material itself also has the disadvantages of poor toughness at room temperature and low strength at high temperature, which limits its further use as a structural material. Therefore, there are still many problems to be solved and explored. Continue to carry out basic research on MoSi2 materials, especially the basic research on the preparation technology and performance of MoSi2 composites, and develop MoSi2 composites with excellent performance, The preparation of MoSi2 and MoSi2 matrix composites with better comprehensive properties is the main subject to be carried out. In a word, in the near future, with the research and development of MoSi2 and its composites, more and better molybdenum disilicide products will be developed, and its application fields will be more extensive.
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